1. Field of the Invention
The present invention relates to a defoaming device and method for aeration, for removing foam produced in an aeration apparatus for sending air into a processing solution, in a case where a photosensitive material is subjected to development.
2. Description of the Related Art
In a developing machine for developing a photosensitive material, aeration is sometimes conducted, i.e., introduction of air into a bleaching solution so as to allow the bleaching solution to recover from its fatigued state. Aeration makes it possible for the bleaching solution to recover from its fatigued state by coming into contact with oxygen contained in the air.
When aeration is conducted, however, numerous bubbles are produced on the surface of the bleaching solution in a bleaching tank, and these bubbles, if brought into the developing tank, can cause contamination of the developing tank.
For this reason, it has been proposed to separate the bubbles or foam on the surface of a bleaching solution into air and bleaching solution respectively, by providing an air-separating column in the aeration apparatus (Japanese Patent Application Laid-Open Publication Nos. 2-33145 and 2-33146). This air-separating structure is so arranged that the foam produced by aeration is introduced into the separating column, and a baffle plate and activated carbon particles disposed in the separating column are made to effect defoaming action. However, deposits can adhere to the activated carbon particles, resulting in the blockage of an air-venting pipe, or the air which has failed to undergo defoaming by the baffle plate flows out of the separating column and causes the lowering of the solution level in the bleaching tank by exerting pressure on the liquid surface, or the foam can enter the developing tank, thereby causing contamination.